1. Field of the Invention
The present invention relates to an exercise therapy device such as an ergometer and a treadmill, and more particularly, to a control apparatus and method for an exercise therapy device capable of controlling interval training so that a high-intensity exercise is an anaerobic exercise and a low-intensity exercise is an aerobic exercise.
2. Description of the Related Art
Hitherto, as interval training, which is commonly carried out as training for an athlete such as a track and field athlete, there is employed a method in which an exerciser alternately and repeatedly carries out a plurality of sets of an exercise to be carried out at a high intensity (hereinafter referred to as “high-intensity exercise”) and an exercise to be carried out at a low intensity (hereinafter referred to as “low-intensity exercise”) (see, for example, Japanese Patent Application Laid-open Nos. 2012-161700, 2007-522862, and Hei 2-14056). The interval training is regarded as enabling an exerciser to enhance, for example, his/her instantaneous power and top speed. In particular, when the high-intensity exercise is an anaerobic exercise, a muscle-strengthening effect can be expected.
However, such a related-art support device for interval training is mainly aimed at prompting an exerciser to follow a target heart rate, which is set depending on an exercise load. In addition, the related-art support device for interval training has only functions of, for example, measuring vital signals such as the exerciser's actual heart rate and notifying the exerciser with sound when the measured heart rate deviates from the target heart rate, and displaying information for distinguishing whether the exercise load is an overload, an appropriate load, or a light load.
Meanwhile, in a field of cardiac rehabilitation for patients with cardiac disease, training with an aerobic exercise that uses an exercise therapy device such as an ergometer and a treadmill is commonly carried out. This is because studies have verified that the life prognosis of the patient with cardiac disease is extended by carrying out an exercise therapy with the aerobic exercise (see, for example, Brandi J. Witt et al., “Cardiac Rehabilitation after Myocardial Infarction in the Community”; Journal of the American College of Cardiology Vol. 44, No. 5, 2004, Elsevier Inc., Sep. 1, 2004, pp. 988-996).
However, among those related-art exercise therapy devices such as an ergometer and a treadmill, there has been no exercise therapy device that is manufactured on the assumption that the exerciser carries out the interval training with the manufactured exercise therapy device. For example, with Japanese Patent Application Laid-open No. 2012-161700, even when an exercise program in which the high-intensity exercise and the low-intensity exercise are alternately repeated can be created, the exercise load of the created exercise program is premised on a heart rate response that is supposed to be reached. In other words, the related-art exercise therapy device is also premised on the heart rate response, as in the related-art support device for interval training.
However, the related arts have the following problems.
According to the New York Heart Association (NYHA) Functional Classification, although depending on the exercise load, a time constant τ for the response of a heart rate is, at a load of 20 W, about 20 seconds to 40 seconds in a case of a healthy person, and about 55 seconds to 100 seconds in a case of a patient with Class III whose severity of heart failure is high. Accordingly, for a practical purpose, an exercise time period of this response time constant τ or longer needs to be set as the exercise time period for one exercise load. An operating time period is thus set to τ or longer in contents of the interval training such as the ones disclosed in Japanese Patent Application Laid-open No. 2012-161700, and hence this interval training does not involve the exercise load for the anaerobic exercise but involves an area for the aerobic exercise in its entire contents.
In addition, a general exercise therapy device includes a display part, which displays numerical values or a graph, as its component so that the exerciser can acquire information on the exercise load. However, the value displayed on the display part has been a value obtained by sampling or averaging the values at regular time intervals, which is designed for each exercise therapy device. Accordingly, although a difficulty in seeing the value due to a dispersion of values is lessened, the peak value within the fluctuation cannot be seen when a load intensity fluctuates within the regular time interval.
As described above, in the related-art exercise therapy device, only the aerobic exercise area is a target of training even when the interval training is carried out. Accordingly, even when the exercise program is created so that the high-intensity exercise is the anaerobic exercise and the low-intensity exercise is the aerobic exercise or a rest state, there have been actually no control apparatus and method for an exercise therapy device capable of appropriately controlling the interval training in order to execute the created exercise program.
As a result, when the exercise therapy device using the heart rate response suited to the aerobic exercise is used to create an exercise program for carrying out the anaerobic exercise, the exerciser becomes short of breath before his/her heart rate rises, and hence control of the exerciser with the heart rate cannot be performed, which is a problem of the related arts. Further, in contrast, even when the anaerobic exercise is to be carried out independently of the heart rate response, a method of accurately carrying out an exercise for an allowable exercise time period that has been prescribed cannot be specified. The time period for the anaerobic exercise thus varies, and hence it is uncertain whether or not an expected effect of the exercise therapy can be obtained, which is another problem of the related arts.
As described above, in the interval training, it is important to execute an allowable anaerobic exercise as accurately as possible. As a method of determining the exercise load for the anaerobic exercise, there is given an exercise prescription in which a one-repetition maximum (1 RM), which is the maximum muscular strength that can be exerted only once, is used as a reference, and a load corresponding to 80% of the 1 RM is prescribed as the exercise load. In order to execute this method, a peak within one rotation needs to be set and displayed when the exercise load is set and the state of the exercise load is displayed in the exercise therapy device. However, with the exercise therapy device which displays only the averaged value, the anaerobic exercise using the 1 RM as the reference cannot be carried out accurately, which is still another problem of the related arts.